1. Field of the Invention
The present invention relates to the technical field of liquid displaying, and in particular to a method for manufacturing an array substrate of a transmissive liquid crystal display (LCD)
2. The Related Arts
Displays that are currently available in the market can be roughly divided into three categories according to the light source used, including transmissive LCD, reflective LCD, and transflective LCD. The transmissive LCD is applicable in conditions of weak surrounding light, such as indoor environment. When used outdoors, due to the intense external light, the intensity of the backlight source is severely affected, making human eyes perceiving excessive panel brightness and thus making image unclear, and eventually affecting image quality. In addition, long term use of the backlight source would lead to a great consumption of electrical power. Since a small-sized display is often powered by electrical battery, it often occurs that power storage soon gets exhausted. The reflective LCD is applicable for conditions with intense external light source for in the structure thereof, a reflector is provided for reflecting away the intense light in order to minimize the influence of the external light source. Such a structure is compact and light-weighted and saves power consumption. However, a problem of insufficient lighting may occurs in the conditions of weak surrounding lighting, and thus affecting the image quality. The transflective LCD has two different display modes. In a dark environment, a transmissive mode dominates, where a backlight source of the LCD emits light through a liquid crystal panel to display image; and in a condition where sufficient lighting exists, such as sunlight, a reflective mode dominates, where a reflector of the liquid crystal panel reflects away the external light to serve as light source for displaying image. Thus, the transflective LCD is fit for various outdoor environments with intense lighting, and can particularly provide excellent outdoor viewability but requires only less brightness of the light source and shows an advantage of low power consumption.
An LCD is generally composed of an upper substrate and a lower substrate between which liquid crystal is interposed. The upper substrate is the so-called color filter substrate, which generally comprises a common electrode and a color filter. The lower substrate is the so called array substrate, which generally comprises thin-film transistor (TFT) and pixel electrode. The color filter substrate forms the color filter through multiple photo-masking operations. The array substrate usually uses four to six masks and is subjected to multiple masking processes including film deposition, mask exposure, and etching to form arrayed arrangements of thin-film transistors and pixel electrodes. The greater the number of mask used in the array substrate manufacturing process is, the greater the number of manufacturing steps has to be taken. This leads to high disqualification rate and makes it hard to control costs.